In a system as described in U.S. Pat. No. 7,826,426, sometimes called a “virtual cell” system, the access points in the wireless communication system are instructed by a control element regarding which access point should service the mobile station, with the effect that the mobile station sees the system as if there was only a single access point servicing it at all times, as if the system were a single “virtual cell” rather than a multiplicity of separate cells. When the control element transfers the mobile station from one access point to another, the receiving access point receives a BSS (basic service set) ID (identifier) which has been associated with the mobile station, and prepares to service the mobile station. As described in U.S. Pat. No. 7,826,426, while a BSSID is generally an ID of a service offered by an access point, in a virtual cell system, each mobile station is assigned its own separate BSSID, which can be transferred among access points so that the mobile station appears to be constantly serviced without any transfers between access points and without any protocol messages exchanged with the mobile station to transfer between access points.
Recent IEEE 802.11 standards include a provision, in 802.11k, which allows a mobile station to request a list of locally available services (called a “neighbor list”) and their BSSID's. Upon receiving the neighbor list, the mobile station can immediately contact a new access point. Before use of 802.11k, the mobile station would commonly have sent one or more probe requests, to which the control element would respond by reassigning the wireless station to a new access point. With use of 802.11k, this can pose a problem because the mobile station may no longer send any probe requests, and the control element would not know what service (if any) the wireless station is going to request and thus would not know to reassign the mobile station to a new access point. The new access point might not have yet prepared to transfer the BSSID associated with the mobile station, and might not have yet prepared to service the mobile station.
Recent IEEE 802.11 standards also include a provision, in 802.11r, which allows a mobile station to conduct a “fast handoff” from a source access point to a destination access point. For example, a mobile station might conduct a fast handoff after receiving a neighbor list as described with respect to the IEEE 802.11k standard. Similar to the ability of the mobile station in 802.11k, in 802.11r, the mobile station may connect to a destination BSSID at the destination access point without sending probe requests, and without the control element knowing ahead of time which destination access point the mobile station is about to transfer to. Similar to the ability of the mobile station in 802.11k, in 802.11r, the destination access point might not have yet prepared to transfer the BSSID associated with the mobile station, and might not have yet prepared to service the mobile station.